Similarly, the Obama Administration decided to partially pull back from a previous move aimed at gaining more U.S. energy independence through the use of nuclear reactors.

Despite these decisions, nuclear energy remains the world's most used source of emission-free energy source. This is particularly true in regions which are densely populated, although it is not entirely clear why.

Only one U.S. plant has been approved since the disaster — Southern Co.'s two reactors at Plant Vogtle site in Georgia. In fact, it is the first nuclear power plant approved in the U.S. in more than three decades. Yet, some U.S. states rely heavily on nuclear energy for generation of electric power, especially as a source of emission-free energy.

Nuclear energy cannot be readily replaced without having a river or huge lake for generating hydro power, without building huge wind farms, and as solar energy is years away. 24/7 Wall St. reviewed the ten states that rely heavily on nuclear power as their source of emission-free energy.

If clean energy is the wave of the future, then it's time for the U.S. to expand on the 104 nuclear plants currently in operation. The push for nuclear power is in hope of producing cheaper electricity without producing air pollutants or greenhouse gases.

Safety is a big concern. Since the 1979 Three Mile Island meltdown, there has been no new construction of nuclear power plants and the Japan earthquake has bolstered recent arguments against more plants.

Currently, 31 of the states have nuclear plants. 24/7 Wall St.'s analysis covers the 10 states in which nuclear energy is the most significant source, or even the only source of emission-free power. In most of these states, the amount of total electricity generated by nuclear is above a third.

24/7 found that these ten states tend to have energy costs per capita above the national average. However, they also tend to be among the most densely populated states, which provokes the "not in my backyard" argument against nuclear power plant construction.

It also questions the usefulness of nuclear power as an alternative to less densely populated states that already have low electric cost per capita, such as North Dakota, Kentucky, Oklahoma, and West Virginia. Coal and gas power are plentiful in these states, which is an advantage, at least until fossil fuel supplies begin to run low.

24/7 Wall St. looked at the ten states that have the highest portion — 95% to 100% — of emission-free power from nuclear power plants using information from the Nuclear Energy Institute. We also looked at population density based on U.S. Census Bureau numbers. U.S. Energy Information Administration provided the number of plants per state.

Only Hawaii has higher residential electricity rates than Connecticut. The Millstone nuclear power station in Waterford produces half of the state's electric power.

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5. Michigan

Enrico Fermi Nuclear Generating Station, Unit 2

Emission-free power from nuclear: 98%

Number of nuclear power plants: 3

Electricity generated by nuclear: 26%

Energy price per capita: 12.8 cents (16th highest)

Population: 9.9 million

Density Rank: 17th

Michigan has large natural gas reserves, which helps to heat homes during the cold winter. The three nuclear facilities in the state are responsible for supplying more than a quarter of the state's electricity.

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4. Florida

Emission-free power from nuclear: 99%

Number of nuclear power plants: 3

Electricity generated by nuclear: 11%

Energy price per capita: 11.7 cents (21st highest)

Population: 19.1 million

Density Rank: 8th

Solar power should have loads of potential in the Sunshine State, but nuclear plants still account for 99% of the emission free power in Florida. Per capita residential electricity demand is high, due in part to high air-conditioning use during the summer.

The August 2011 earthquake near the North Anna facilities caused an automatic shutdown and concern, although both reactors reopened shortly after and remain in operation. The plant's owner, Dominion, said the seismic event exceeded the plant's design basis. But, inspections found no damage.

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2. New Jersey

PSE&G nuclear complex in New Jersey.

Emission-free power from nuclear: 100%

Number of nuclear power plants: 3

Electricity generated by nuclear: 50%

Energy price per capita: 16.1 cents (7th highest)

Population: 8.8 million

Density rank: 1st

The most densely populated state is home to the nation's oldest nuclear operating facility, Oyster Creek, which has been running since 1969. An offshore wind farm has been approved by the New Jersey Board of Public Utilities off the coast of Cape May which would add to the state's emission free power base